20547978 has 64 divisors (see below), whose sum is σ = 47222784. Its totient is φ = 5953200.

The previous prime is 20547973. The next prime is 20547983. The reversal of 20547978 is 87974502.

It is an interprime number because it is at equal distance from previous prime (20547973) and next prime (20547983).

It is not an unprimeable number, because it can be changed into a prime (20547973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 247525 + ... + 247607.

It is an arithmetic number, because the mean of its divisors is an integer number (737856).

Almost surely, 2^20547978 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20547978, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23611392).

20547978 is an abundant number, since it is smaller than the sum of its proper divisors (26674806).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20547978 is a wasteful number, since it uses less digits than its factorization.

20547978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152 (or 130 counting only the distinct ones).

The product of its (nonzero) digits is 141120, while the sum is 42.

The square root of 20547978 is about 4532.9877564361. The cubic root of 20547978 is about 273.8985274352.

The spelling of 20547978 in words is "twenty million, five hundred forty-seven thousand, nine hundred seventy-eight".